(19)
(11) EP 0 428 387 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.02.1992 Bulletin 1992/09

(43) Date of publication A2:
22.05.1991 Bulletin 1991/21

(21) Application number: 90312385.9

(22) Date of filing: 13.11.1990
(51) International Patent Classification (IPC)5: C01G 33/00, C01G 49/00, C01G 51/00, C01G 37/00, C01G 53/00, C01G 45/00, C04B 35/49
(84) Designated Contracting States:
DE FR GB

(30) Priority: 13.11.1989 JP 294183/89

(71) Applicants:
  • SAKAI CHEMICAL INDUSTRY CO., LTD.,
    Sakai Osaka (JP)
  • DIRECTOR-GENERAL NATIONAL INSTITUTE FOR RESEARCH IN INORGANIC MATERIALS
    Tsukuba, Ibaragi (JP)

(72) Inventors:
  • Terada, Yasujiko
    Ashiya, Hyogo (JP)
  • Uno, Hajime
    Sakai Osaka (JP)
  • Abe, Kazunobu
    Izumi, Osaka (JP)
  • Shirasaki, Shinichi
    Tsukuba, Ibaragi (JP)

(74) Representative: Geering, Keith Edwin et al
REDDIE & GROSE 16 Theobalds Road
London WC1X 8PL
London WC1X 8PL (GB)


(56) References cited: : 
   
       


    (54) Process for producing powder material for lead perovskite ceramic


    (57) A process for producing a powder material for niobium-containing lead perovskite ceramics represented by the general formula:
    PbAxNb1-xO₃,
    wherein X = 1/2 or 1/3 and A represents at least one element selected from Fe, Co, Cr, Ni, Mn, Mg, Zn, Cd, Zr, In, Cu and Hf. A dried mixture of a sol or suspension of a hydroxide of A (which has a lower activity than Pb) and a niobic acid sol is first calcined A Pb compound is then added to the mixture and the resul­tant mixture is calcined again.





    Search report